Pump, method for manufacturing pump, and refrigeration cycle device
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Solution Overview
Problem
The magnet pump motor's performance is reduced due to the increased distance between the stator and rotor magnet caused by covering the outer peripheral surface of the rotor magnet with thermoplastic resin, leading to potential cracking from thermal shock during cold/hot water cycles.
Innovation Solution
A pump design featuring an annular rotor unit with through holes extending axially, where these holes are embedded in thermoplastic resin during integral molding, preventing magnet cracking without covering the outer magnet surface with resin.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the outer peripheral surface of the rotor magnet is covered with thermoplastic resin, then the magnet is protected from thermal shock, but the distance between the stator and rotor magnet increases reducing pump performance
Solution Approach 1:
The magnet is divided into multiple segments with through-holes that allow resin penetration. The resin enters these through-holes and anchors the magnet segments internally without requiring external coating, thus protecting against thermal shock while maintaining close spacing between stator and rotor.
Solution Approach 2:
The thermoplastic resin is nested within the through-holes of the magnet structure rather than coating the external surface. This internal nesting provides protective reinforcement while keeping the magnet's outer dimensions small, ensuring minimal distance between stator and rotor surfaces.
2Reliability
If the outer peripheral surface of the rotor magnet is covered with thermoplastic resin, then the magnet is protected from thermal shock, but the pump performance is reduced
Solution Approach 1:
The magnet is segmented with through-holes that enable internal resin reinforcement. This segmentation provides thermal shock protection through internal anchoring while avoiding external coating that would increase air gap and reduce magnetic coupling efficiency, thus preserving pump power performance.
Solution Approach 2:
The thermoplastic resin acts as an intermediary material that penetrates and anchors within the magnet's through-holes. This intermediary reinforcement provides thermal shock resistance without forming an external insulating layer that would reduce magnetic field coupling and pump performance.
3Reliability
If thermoplastic resin is used to protect the magnet, then cracking from thermal shock is prevented, but more resin is required increasing cost and complexity
Solution Approach 1:
The protective function is extracted from external surface coating and relocated to internal through-hole anchoring. This extraction eliminates the need for excessive resin material, as the resin only needs to penetrate and anchor within the through-holes rather than forming a thick external protective layer.
Solution Approach 2:
The magnet incorporates a porous structure with through-holes that allow minimal amounts of thermoplastic resin to penetrate and provide reinforcement. This porous design enables effective thermal shock protection with reduced resin quantity, lowering material costs and manufacturing complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The embedded resin securely holds the magnet, reducing cracking from thermal shock and allowing closer stator-magnet alignment, enhancing pump performance and reducing resin usage while maintaining cost-effectiveness.
Implementation Method 1
each of the through holes is embedded in the thermoplastic resin that constitutes a part of the resin portion
Implementation Method 2
a rotor having an annular magnet, a sleeve bearing provided inside of the magnet
Data Source
AI summary
A pump is provided that includes a molded stator having a substrate on which is mounted a magnetic-pole position detection element and that also includes a rotor having a rotor unit with one end thereof in an axial direction being opposed to the magnetic-pole position detection element and the other end thereof in the axial direction being provided with an impeller attachment unit. The rotor unit includes a magnet, a sleeve bearing, and a resin portion formed from a thermoplastic resin that is used for integrally molding the magnet and the sleeve bearing and that constitutes the impeller attachment unit. The magnet includes a plurality of through holes that each extend in the axial direction; and each of the through holes is embedded in the thermoplastic resin that constitutes a part of the resin portion.